My favorite phone EVER which I owned, was the Motorola Q8 (GSM Version), but it was disappointing because it didn't have 3G (unlike the CDMA version of Verizon and Sprint - which had 3G via EV-DO)

I later bought the the Q9, but I really disliked the look of it, plus it didn't have global 3G, only country specific, so I ended up returning it!
Q9:

Nice! I've had both those treo's, I stopped at the 750, and switched to RIM/Blackberry then
the treo was one of the best (at the time) and most advanced smart phones out there, only thing sucked is it weighed a ton
but was good for a weapon as well, heh.. my favorite overall phone ever was a Sony Ericsonn Walkman model w mp3 walkman..

Best overall phone ever, great interface, like Nokia used to make, just well planned and laid out, no unnecessary fluff
amazing camera, great mp3 player, video recorder, great size, awesome keyboard...just 10/10 all around, and it came with stereo in ear bud's (when they were new and high end at the time) that doubled into a mic/earphone set.